Biomechanics Of Porcine Brain Tissue Under Finite Compression

While the developments in finite element method have made it possible to simulate the complex problems in biomechanics, building an accurate constitutive model of living tissues is a major factor in getting reliable finite element analysis (FEA) results. In this study, a set of experiments were performed to test the properties of porcine brain tissue under unconfined uniaxial compression with 20 s hold time at varied strain levels (10-50%) and strain rates (0.1-1 s(-1)). A novel method was developed to build a quasi-linear viscoelasticity (QLV) model. The elastic function and the relaxation function were calculated separately. An Odgen model was adopted to characterize the elastic behavior, while the relaxation response was modeled at six decay rates. A standard to choose the visco parameters was discussed and carried out. The disparity of parameter values in previous models was discussed and explained. It is suggested that this model should be used in the tested loading conditions (relaxation time, strain rate, strain levels).